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Hi everybody. I'm posting this in the "general section" because i thought it's the most suitable.
I have a hunwei Raptor katana and i'm experiencing serious rust trouble. I have already tried cleaning the rusty spots using a soft sandpaper and it worked but the rust keeps coming back.
One member of our dojo who has a Samurai Bugei katana had the same problem as well and whatever we did (sandpaper, changed the oil, keeping the katana cleaning schedule tighter) the rust always comes back.
I would be grateful if anybody can offer any advice about that problem. I hope that Keith Larman sees this thread because his insight would be valuable in order for us to overcome the rust problem.
Thanks in advance!

Hi everybody. I'm posting this in the "general section" because i thought it's the most suitable.
I have a hunwei Raptor katana and i'm experiencing serious rust trouble. I have already tried cleaning the rusty spots using a soft sandpaper and it worked but the rust keeps coming back.
One member of our dojo who has a Samurai Bugei katana had the same problem as well and whatever we did (sandpaper, changed the oil, keeping the katana cleaning schedule tighter) the rust always comes back.
I would be grateful if anybody can offer any advice about that problem. I hope that Keith Larman sees this thread because his insight would be valuable in order for us to overcome the rust problem.
Thanks in advance!

I had/have the same problem with my Raptor. I'm beginning to think it may have something to do with the saya.

First question is whether you cut with the sword. If you do, do you return the sword to the saya after cutting without first cleaning the blade *thoroughly*? If you don't, most likely gunk has gotten in to the saya and that is notoriously hard to fix. There are long saya rasps we have, but they are god-awful expensive. And I can rasp and rasp and still not get whatever it is that is causing the problem.

Another issue (which is actually rather common) is people will overoil the blade. That this might seem to be a good thing, but what in fact happens is that when there is too much oil the oil gets left behind in the saya, rubbed in to the walls, etc. Eventually the wood will swell a bit and the saya walls begin to contact the blade in places where it shouldn't. Then when you return the blade to the saya any contamination that might be on the blade tends to get "grabbed" by the swollen area. This will cause repeated scratches and/or rust areas if whatever is caught is caustic to the blade. This can also be stuff like finger oil or most anything, even stuff floating in the air.

The bottom line is that if you put your blade back in the saya without cleaning it first, especially if you handle the steel itself or are cutting, you run the risk of contaminating the saya. If you over-oil the blade you will dramatically reduce the useful life of the saya and increase the odds of scratches, scuffs and rust.

So oil it, wrap it up in something else, put it somewhere safe, and wait a few days. If it doesn't form rust, clean it, oil it, and put it in the saya for a few more days. If it forms again you know it's the saya. If not... Clean it better. Sandpaper is okay on stuff like raptors, but will ruin the finish and should never be used on an antique or remotely correctly polished blade. Instead of sandpaper you might try just using something like Noxon. It is relatively low abrasion and has good ingredients that will neutralize stuff that causes oxidation. Just work the area gently.

Robert thank you for taking the time to reply.
Keith, your insight was very enlighting as always. Thank you very much for your information and your time. I realise now that putting too much oil is probably the root of our trouble. Thank you once again!

I've only cut a couple times with mine and wiped it clean after both occasions. As for oiling, I put on a light coat, didn't overdue it.

The rust/discoloration patches occurred a few inches below the kisaki and about 4"-5" up from the tsuba. They appeared on both sides of the blade as well.

Was wondering if this could be some kind of reaction to whatever glue was used to afix the two halves of the saya together.

Anything is possible of course, but over the years with Bugei's stuff I've not seen that. We've had virtually zero rust problems with their swords. I have seen a few folk who've had rust problems start years later, but it's really difficult sometimes to pinpoint why that might happen. Also keep in mind that all sorts of things can cause problems. One customer of mine had recurring problems with rust along the mune of his sword. The problem turned out to be how he did noto (resheathing). It turned out his skin oil was massively corrosive. And even though he thought he cleaned it well the reality was that if *any* was left behind for any time (especially on hot days) it would rust almost instantly. I pointed out to him that where he was getting the rust is exactly where he touches the piece so I had him rub another blade I had (unpolished) on his hand and put it on my rack. Just to show him I rubbed another area on my skin. His area rusted in a day. Mine didn't. Some peoples' body chemistry is also vastly more nasty. And those who use some lotions also have more problems.

But sometimes it just is what it is. Heck, I just helped out a guy who had a sword that was mounted probably 100 years ago that he's had for 20 years that just started a similar problem in one area. So 80 years of no problems. Then suddenly... Something is in the saya. How it got there, why it waited until now, etc. are all questions I can't answer. And the customer tells me it sits on a rack on his shelf untouched other than a cleaning every few months. As of now my only suggestion to him is offer to make him a shirasaya or a replacement saya for it. Shrug.

Carbon steel "likes" to rust. And depending on environment, location, etc. it will. People who live by the ocean in particular have many more problems fwiw. People in hot dry areas have few (although their mounts tent to dry out and crack). Nature of the beast.

To capitalize a little on Keith's comments regarding over-oiling blades, I oil my blades the same way I do my firearms. Just as my drill instructor taught me, I apply the oil and then wipe off all the oil possible. That results in a very light coat of oil over the metal surfaces and is sufficient to prevent rust. Using that method I've never, ever had a firearm rust and haven't had any problem with the four blades I own either. Keith may want to weigh in here and discuss his views on oiling and over-oiling.

What MIchael said -- oil it with a clean cloth then take another dry, clean cloth and try to get it all off. Take it out a day later and wipe it again with a dry cloth and you'll see there's a *lot* more on the blade than you thought.

Oh, also, proper oil is a must. With inexpensive shinken I have *zero* problem using something like breakfree CLP. I hate the smell of the stuff, but it is good stuff. On antiques and well done blades I stick with medical grade light (and I mean really light) mineral oil. Or simply buy a bottle of so-called choji oil (super light grade mineral oil with a drop of clove for that lovely smell). If you're using it correctly a single small bottle of sword oil (Bugei sells the stuff from Japan as do a couple other places) should last years on a single sword. You might want to buy a bigger one if you have a bunch or are always cutting.

Another thing is cleaning the blade. Uchiko is fine and traditional, but you can also hold the sword tip pointed down and gently cover the blade with an ammonia based window cleaner (windex). Use a clean cloth clean the sword as if you're cleaning a window (wipe off the streaks). Then oil. Hold it point down so the windex doesn't seep under the habaki.

You can also use high percentage alcohol (91% or greater) to clean blades. The stuff strips the daylights out of the old oil so be sure to reoil right away.

Really it's not brain surgery. Too much oil is a waste and damaging to the saya and possibly the blade. You only need the thinnest of coatings (it simply blocks the air from the surface of the steel -- oxidation requires oxygen). So keep the blade scrupulously clean, keep your skin oil off the blade (stop touching the damned blade), and keep the surface protected with a sheen of oil.

And for you guys having problems with rust spots, you might try breakfree instead. It has stuff in it to neutralize bad stuff so it might be just the ticket for you. Still, thin as possible. And keep in mind that solvents don't always mix well with paints, lacquers, glues, etc. hence why I never use the stuff on antiques. But for an inexpensive training blade I see no reason not to use something like breakfree. It really is very good for what it is intended for. Just hit a gun store on on-line supply (I think Brownell's carries it). Breakfree CLP. Spray can or spray bottle will last your lifetime if you use it right. Tiny little spurt on a cloth. Wipe on, wipe off.

Keith would I be right in suggesting that in likely damp condition it's better to store the blade out of the scabbard? Perhaps wrapped in oilcloth or anti-rust waxed paper.
An acquaintance has parts of his cheapo carbon blade rust when his parents left it some months in the garage. I thought it a mistake to leave it there in its scabbard ...

Well, non stainless blades might need to be cared for periodically. It is just the nature of the beast. Especially if you live close to the ocean with the salt in the air, well, it is just prudent to clean and oil every few weeks. You could try oiling it and wrapping it in plastic wrap to create an air tight seal. Often if you're judicious it can then be put back *gently* in to the saya. But really most of the time in the saya is just fine as long as you oiled it correctly. Yeah, once every few months give it a wipe, but in *most* areas that should be fine.

I disagree with Keith on part of this.....you must be careful of doing an airtight wrapping on any steel tool. With a significant temperature difference, condensation can occur and cause rusting. Hunters who are hunting in snowy or cold conditions learn to leave their rifles outside and not bring them into a heated cabin because they will almost immediately begin to rust. I think you would be alright if the temp is controlled and constant however. I just wouldn't clean, oil and wrap a blade outside in my unheated garage during the winter and then store inside my heated home. Just an extreme caution worth mentioning.

Yeah, you are of course right -- I didn't expand enough. Those who wrap them will do it only on a dry day. Oil it and wrap it completely *and* tightly sealing it in. And it's still not a long term solution, really, but more for those who are leaving it for a couple months. Oil it well.

Better though, IMHO, is to simply clean it periodically and reoil. Or if it's not a high end blade in professional polish just use something like breakfree CLP. That stuff is fantastic.

But also keep in mind that a properly fit saya done by a professional should create what is for all intents and purposes a fairly air tight and stable environment. I'd keep it away from temperature variations, but really if it is done correctly it shouldn't be much of a problem.

I have a customer who lives damned near on the ocean. He has one of those vacuum sealing units. He'll clean and oil the blade, replace it in the saya, then pack the sword in a normal fabric storage bag. He'll toss a couple desiccator packs (the type you buy to put in gun safes) in a long bag (you can buy the seal-a-meal bags in rolls) and seal it up. Voila, sealed environment, dry, etc. I don't know what effect it might have long term on the wood of the mounts, but for keeping the blades rust fee it seems to work for him.

Since I enjoy cleaning, oiling and just examining my blades, I just do it frequently and haven't had any problems. My blades are all modern (and inspected by Keith before I bought them BTW), but I still find subtle nuances every time I look at them. Cleaning and oiling, for me, is a pleasure rather than a chore.

I'm in the process of cleaning the saya and i have some questions about those rasps you have mentioned:

1. Are they for sale, can they be found in the Bugei or Hunwei products?

2. How long are they, will they rich at the end of the saya?

3. Is extensive use of the rasp capable of damaging the wood of the inside of the saya if it has already swollen?

Keith, your insight so far has been immense and it has helped very much so i'm looking forward to your answer.

Thank you once again for your advice!

Been on vacation visiting my wife's relatives in "old Hawaii" and hiking volcanoes... Taking a morning off for coffee at a place with free wifi, so howdy...

The only place selling one made for saya is Namikawa Heibei in Japan. They have a website. The rasp is expensive, around 150 US if memory serves. And yes, the one made specifically for saya reaches the very end of the saya.

And to answer 3, if it is already swollen it may be a lost cause. It is already severely damaged so rasping it out can't make matters worse. And the rasps remove very little material so it would take a while to do any significant removal.

Aloha... Back to enjoying my green tea as the wife (who is in fact Japanese) has the strong american coffee... Now to work on convincing my family that we could just move to the big island of Hawaii since I can work anywhere... Of course the grandparents on the mainland would probably hunt us down and kill us for moving their grandkid far away. And I'm not sure the somewhat translucent lily white (now deeply red) skin on my Norwegian body would last long here...

I use a product called "Frog Lube". It is modern and old thinking product. Made from plants and safe on the skin. It makes carbon steel semi-stainless in my experience, kinda like seasoning a frying pan.

I used it on wood items also. I have sensitive skin and it does not mess me up. I don't know if it would
sit with traditional martial artist. Bottom line is I have no rust where I use it.

Keith thank you once again for your information, it's always helpful. I wish that you rest and enjoy the rest of your vacation.
John, thank you very much for taking the time to reply and help. I have no idea about that product so I will just wait for Keith's opinion about it.